QUESTION #561

When a car is driving up a hill, is the friction between the tires and the ground static friction or kinetic friction?

Asked by: Weiyin He

Answer

If you are not spinning your wheels on the pavement, it is static friction between the tire and ground. If the wheels start spinning, it is kinetic friction. Since static friction provides a greater frictional force than kinetic friction, spinning tires should be avoided. That is the theory behind ABS braking, and why you shouldn't just spin your tires faster when trying to move on slippery pavement.
Answered by: Paul Walorski, B.A., Part-time Physics/Astronomy Instructor